Volcanic Activity Worldwide: Wednesday June 1, 2016

Bromo (East Java, Indonesia): Our expedition leader Andi currently on location reported that the volcano’s activity has been increased since 4 days ago, with visible activity consisting of mild phreatic explosions and strong steaming.
The volcano observatory has been registering continuous tremor as well. Small ballistic ejecta (bombs) can be seen from the rim of the crater.

Semeru (East Java, Indonesia): The activity has not changed significantly for several months at Java’s highest and most active volcano. The lava flow on the upper southern flank of the volcano remains active. Due to the steep incline, incandescent rockfalls from its side and front are relatively frequent.
This effusive activity is also accompanied by ongoing explosive activity: intermittent, small to moderate strombolian explosions from the summit vent.
While these explosions have been occurring relatively frequently, their average size has been much smaller than several years ago, when the volcano’s typical activity had been best characterized by vulcanian-type explosions, a few daily strong blasts generating ash columns rising up to a few km (with no or little effusive activity on the other hand). This difference could be explained by a change towards less viscous lava being erupted recently, allowing for easier degassing and effusive activity.

Dukono (Halmahera): Ash emissions from the volcano continue to occur almost daily. This morning, the ash plume monitored by Darwin VAAC extended 30 km to the WNW.

Colima (Western Mexico): The activity of the volcano remains essentially unchanged, currently relatively low: infrequent small to moderate explosions produce ash plumes that rise 1-2 km, accompanying the very slow growth of a lava dome inside the summit crater.

Turrialba (Costa Rica): Activity has decreased significantly during the past days. Since 2 am local time on 27 May, RSN has detected a substantial and abrupt decrease in the level of seismic activity, which also marks the end of the most recent period of frequent, moderate ash emissions.
During the past days, seismic activity has been dominated mainly by small low-frequency volcanic earthquakes and harmonic tremors of very low energy and short duration, reflecting internal fluid movements.
When not obscured in clouds, only a steam plume can be seen emerging from the active crater. No recent ash falls or sulfur smells in the Central Valley have been reported.

Nyiragongo (DRCongo): One of the local mountain guides reported that as of 30 May, no more lava flows from the side vent were active and cascading into the main lava lake, although lava bubbling could still be seen at the side vent.
Our next group will visit the volcano from 18-21 June and hopefully be able to report the volcano’s current activity in more detail.

Bristol Island (United Kingdom, South Sandwich Is): Eruptive activity continues at the remote volcano and might have become more intense recently.
Satellite images from past days show ash emissions that appear stronger and more regular than earlier on, drifting into northeasterly directions. Also, recent imagery shows a dark patch on the island itself, near the summit, which could be a new cinder cone and/or associated lava flows.
According to the South Sandwich Islands Volcano Monitoring Blog‘s latest update, the recent satellite images “show some faintly dark lines suggesting the presence of lava flows and also a dark patch just west-northwest of the Mount Sourabaya area.”